A person may experience pain or limited mobility as a result of a variety of spinal conditions including trauma, deformity, disease, or other degenerative conditions. Existing methods of treating these conditions include surgical decompression of the affected area of the spine. One such technique employs the use of an interspinous implant device which is inserted between adjacent spinous processes to distract and maintain the desired spatial relationship of the adjacent vertebrae. In coordination with the interspinous device, a securing mechanism, such as a cable or strap, is used to further maintain the position of the spinous processes relative to the interspinous device.
There are a number of limitations of existing interspinous implant devices used in conjunction with a securing mechanism, including the inability to be inserted through minimally invasive surgical procedures and the inability to accommodate the distinct anatomical structures of the spine.
For example, U.S. Pat. No. 6,582,433 to Yun discloses a spacer which does not have a reduced profile insertion orientation, thereby requiring the spinous processes to be distracted further prior to insertion. Similarly, U.S. Patent Publication No. 2007/0233082 to Chin et al. disclose having an insertion profile larger than the desired final distraction spacing of the adjacent spinous process. Further, Chin et al. disclose the use of tools to engage the adjacent spinous processes to aid in insertion of the fixation device.
Alternatively, while some prior art implants include a reduced insertion profile they do not include a means of securing the implant device after insertion. For example, U.S. Patent Publication No. 2009/0149886 to Zentes et al. discloses an implant device which is pivotable between an insertion profile and an operable profile. To provide easier insertion of the implant between the adjacent spinous processes, the size and configuration of the tool engagement end of the implant is limited. Based on these restrictions, the implant includes an integral latch which locks the implant in place once shifted to the operable profile. However, by locking the implant automatically upon being pivoted to the operable profile, the implant cannot be easily repositioned, removed or replaced.
Accordingly, there is a need for an implant device which can be inserted with minimal trauma to the spinous processes and the surrounding tissues and can maintain the desired spatial relationship of the spinous processes after insertion.